The present invention relates to the field of computer peripherals. More specifically, it relates to an apparatus that receives removable peripheral devices.
Advancing technology enables the electronic companies to design and manufacture new peripheral devices for today's computer systems. These devices offer either new designs or an improvement to the existing designs. Among the attributes of these devices are their size, speed and, where applicable, capacity. The biggest advantage of these devices is their size. The manufacturers are able to package a complete and operable device in a housing as small as a standard credit card in width and length, with a thickness of less than 3/4 of an inch.
Among these new devices are those designed to fit the limited size of lap top computers. These devices take advantage of a new standard called Personal Computer Memory Card International Association ("PCMCIA"). This standard was originally used in designing portable solid state memory cards. However, it is becoming increasingly popular in the electronic industry, specifically it is used in the industry supporting lap top computers. For example, hard disk drives, modems, ethernet cards, etc., are being designed using the PCMCIA standard.
As mentioned above, the biggest advantage of these devices is their small size, which makes them easily portable. This feature makes these devices very attractive for use in desk top computer systems. A manufacturer or user of desk top computers can fit up to four of these devices in half of the area allocated for standard 51/4 inch floppy disk drive bays. However, these devices require bays that allow them to interconnect with the desk top host computers. The existing bays for desk top computers fall into two categories. One category comprises those bays that have no ejections mechanism; thus, the user must physically pull the device out of the bay. The second category comprises those bays that have some sort of eject mechanism. However, there are some problems associated with their eject mechanism. The following is a description of how a bay according to each of the above two categories operates.
FIG. 1a illustrates a bay 10 according to the first category of prior art. To use a PCMCIA device, the user must insert the device into recess 12 and push it in so that the PCMCIA connector of the device fully interconnects with the PCMCIA connector of bay 10. To remove the device, the user must manually pull the device out of bay 10.
FIG. 1b illustrates a bay 20 according to the second category of prior art mentioned above. To use a PCMCIA device, the user must slide the device into cavity 22. The PCMCIA device slides in with the help of guiding rails 24. The male PCMCIA connector 26 in the back of bay 20 connects to the female PCMCIA connector of the particular device. The computer communicates with the device through an interface board and the connectors. The interface board is connected to one of the interface slots of the computer. The interface board generates the necessary signals which both the PCMCIA and the host computer can understand. To eject the device, lever 28 must be pushed in the direction of the arrow. This causes a plate 30 at the back of bay 20, underneath connector 26, to push the device out of the bay. The following is a description of the problems associated with the bays from both categories.
When the devices in either of the above two bays communicate with the host computer, they are constantly either sending data to the host computer, or receiving data from the host computer. When the user desires to disconnect the device from either of the two bays, the computer must be notified before the two PCMCIA completely disconnect so that it may complete the task it is currently executing. This task may comprise communication of important data between the device and the computer. Furthermore, to prevent any possible damage to the device, there may be a need to disconnect the power to the device before it is disconnected from the bay.
The advance notice is necessary to prevent any possible loss of data caused by an abrupt halt of the data communication, or to prevent possible damage to the device. The advance notice requires the communication of a signal to the host computer which represents the intent-to-eject before the complete ejection takes place. In addition, the time lapse between the reception of the signal by the host computer and the complete ejection must be sufficient for the host computer to either complete the task that it is executing, for example data communication, or disconnect the power to the device. "Complete ejection" refers to the case where the PCMCIA of the bay is completely disconnected from the connector of the device.
The bays in the two categories mentioned above take advantage of the unique length of two of the pins, one on either side of the connector, of the PCMCIA connector to generate an intent-to-eject signal. These two pins are shorter than the other pins of the PCMCIA connector. When the plate under connector 24 pushes the device out of the bay, or when the user manually pulls the device out, these two pins are first to separate from the corresponding holes of the PCMCIA connectors of either bays. The interface board detects this condition and sends a signal to the host computer. Responding to this signal, the host computer either completes the task being currently executed or disconnects the power to the device. However, sometimes the length of this period, which is from the moment the interface board detects the intent-to-eject to the moment the device completely separates from either of the two bays, is not sufficient for the computer to complete the task it is executing or to disconnect the power from the device. In these situations, the ejection leads to loss of data being transferred between the device and the host computer or results in damage to the device. Although, the problem is associated with both bays, it is more noticeable where the user must manually remove the device from the bay. Sometimes, the user removes the device so fast that there is almost no time for the host computer to react to protect the data or the device.
The second problem is the price of the present bays, specifically bay 20 in FIG. 1b; each PCMCIA connector and eject mechanism costs more than $8.00 which greatly increases the cost of the present bays. Where a low cost computer system is desired, the current bays may not be the ideal solution.
Finally, some peripheral devices require external connection to a telephone line or other equipments. For example, a fax/modem card requires external connection to a telephone line. These devices normally have a receiving connector allowing them to connect to the cable from the telephone jack or from other equipments. If the bay is connected to the front of the host computer, the external cable must be connected to the device on the front of the host computer. This could cause problems when several of these devices requiring external connections are connected to the host computer. For example, if a fax/modem and an ethernet peripheral device is connected to the host computer, there will be one cable connecting each of the two devices to the telephone jack. If only one telephone line is being used, the user must physically switch the telephone cables connected to the telephone jack depending on which device is being used. In addition to the inconvenience of switching the telephone cables, there is always a chance of connecting the wrong cable to the telephone jack, especially where more than two or three telephone cables are hanging from the front of the computer.
One solution to this problem is to connect the bay to the rear of the chassis of the host computer. This would eliminate the cluster of cables in front of the host computer; however, it requires turning the computer chassis each time a device needs to be connected or disconnected. This may not be feasible where the user has one bay and needs the services of several peripheral devices.
Therefore, it can be appreciated that there is a need an improved bay to be used in the desk top computer systems. A bay that has a better ejection mechanism, cheaper price, and a solution for external connections.